Variable capacitor and method of making the same

Abstract

A capacitor manufacturing method provides variable capacitors whose capacitances remain stable under the influence of temperature change. Such a variable capacitor includes a fixed electrode, a movable electrode film facing the fixed electrode, and an anchor portion that provides partial connection between the fixed electrode and the movable electrode film. For making this variable capacitor, a first electrode is formed to serve as the fixed electrode. Then, an anchor portion is formed on the fixed electrode, and a sacrifice film is formed to cover the fixed electrode but partially expose the anchor portion. A second electrode is formed on the sacrifice film to serve as the movable electrode film, bonded to the anchor portion. Finally, the sacrifice film is removed.

1 - 8 . (canceled) 
   
   
       9 . A variable capacitor comprising:
 a first movable electrode film and a second movable electrode film facing each other; and   an anchor portion for providing a partial connection between the first movable electrode film and the second movable electrode film.   
   
   
       10 . The variable capacitor according to  claim 9 , wherein the anchor portion penetrates at least one of the first movable electrode film and the second movable electrode film. 
   
   
       11 . The variable capacitor according to  claim 9 , further comprising a dielectric film provided between the first movable electrode film and the second movable electrode film, wherein the dielectric film is held in contact with one of the first movable electrode film and the second movable electrode film. 
   
   
       12 . The variable capacitor according to  claim 11 , wherein the dielectric film has a portion constituting at least part of the anchor portion. 
   
   
       13 . The variable capacitor according to  claim 11 , wherein the first movable electrode film and the second movable electrode film are pressable against each other via the dielectric film. 
   
   
       14 . The variable capacitor according to one of  claim 11 , wherein the first movable electrode film and the second movable electrode film are partially pressable against each other via the dielectric film. 
   
   
       15 . The variable capacitor according to  claim 9 , wherein the first movable electrode film has a portion curved toward the second movable electrode film. 
   
   
       16 . The variable capacitor according to  claim 9 , wherein the first movable electrode film has a portion curved away from the second movable electrode film. 
   
   
       17 . The variable capacitor according to  claim 9 , wherein the second movable electrode film has a portion curved toward the first movable electrode film. 
   
   
       18 . The variable capacitor according to  claim 9 , wherein the second movable electrode film has a portion curved away from the first movable electrode film. 
   
   
       19 . A method of making a variable capacitor, the method comprising the steps of:
 forming a first electrode on a substrate;   forming an anchor portion on the first electrode;   forming a sacrifice film which covers the first electrode and partially exposes the anchor portion;   forming a second electrode on the sacrifice film to be bonded to the anchor portion; and   removing the sacrifice film.   
   
   
       20 . A method of making a variable capacitor, the method comprising the steps of:
 forming a first electrode on a substrate, the first electrode being formed with an opening;   forming an anchor portion including a part fitting into the opening and a part projecting beyond the first electrode;   forming a sacrifice film which covers the first electrode and partially exposes the anchor portion;   forming a second electrode on the sacrifice film to be bonded to the anchor portion; and   removing the sacrifice film.   
   
   
       21 . A method of making a variable capacitor, the method comprising the steps of:
 forming a first electrode on a substrate;   forming a sacrifice film covering the first electrode, the sacrifice film being formed with a first opening for partial exposure of the first electrode;   forming a second electrode on the sacrifice film, the second electrode being formed with a second opening communicating with the first opening;   forming an anchor portion on the first electrode to penetrate the sacrifice film and the second electrode by filling at least the first opening and the second opening with a material; and   removing the sacrifice film.   
   
   
       22 . A method of making a variable capacitor, the method comprising the steps of:
 forming a first electrode on a substrate, the first electrode being formed with a first opening;   forming a sacrifice film covering the first electrode, the sacrifice film being formed with a second opening communicating with the first opening;   forming a second electrode on the sacrifice film, the second electrode being formed with a third opening communicating with the second opening;   forming an anchor portion to penetrate the first electrode, the sacrifice film and the second electrode by filling at least the first opening, the second opening and the third opening with a material; and   removing the sacrifice film.